Wescan Tertiary Filter page2

The SFSBW series of skid mounted tertiary filters have been engineered to provide maximum efficiency pressure tertiary filtration in a unit with a small footprint and minimal installation costs. These package systems come complete with filter tank including all internal piping, pumps, motors, valves, control panel and factory wiring. The filtration system is factory assembled on a heavy gauge steel base designed to minimize shipping and installation costs. Systems with dual pumps for 100% back-up protection are also available.

The filter feed pump (dosing pump) draws water, which has to be filtered, from the feed tank. It passes this water through the automatic backwash filter and out of the discharge into the outfall tank.

This filter feed pump is turned on and off by a differential float switch. There is a delay timer in the control panel which delays the starting of the filter feed pump. This is to allow the filter media time to re-settle after backwashing.

In the filter feed tank is a float switch which operates a high water alarm in the control panel if the filter feed pump fails. If the filter feed pump fails, the water will bypass the filter and flow by gravity into the outfall tank (backwash pump feed tank) if it is piped and plumbed per our drawings.

On the filter tank is a pressure differential switch, When the pressure in the filter tank reaches a predetermined level, the switch makes an electrical contact which does the following:

- Turns on the compressor.

- Energizes the solenoid valve.

- Turns on the backwash pump. (note: the pump is interlocked so the filter feed pump cannot run when the backwash pump is running)

In the control panel is a timer for the backwash pump. It is factory set to operate the backwash pump for the required backwash time.

If the backwash pump empties the outfall tank before the timer stops the pump, then the safety float switch will turn off the backwash pump to prevent it from running dry.

When the air compressor starts to operate it pressurizes the two hydraulic flow control valves which reverses the open/closed position of these valves.

The air compressor runs for the same time period as the backwash pump as it is connected to the same timer.

When the air compressor and backwash pump stop running the hydraulic flow control valves return to their original postion and the filter is now ready to continue its normal filtering cycle.

These skid mounted multi-media tertiary pressure filtration systems can be expected to produce a high quality filtered effluent with < 5 mg/l BOD₅ and < 5 mg/l TSS when used in conjunction with the following equipment: